A tubeless tire is used commonly as a tire for an automobile. A basic structure of the tubeless tire is shown as FIG. 31. A pair of side wall 2 covers from both side edges of a tread part 1 to a rim 5, the edge of the side wall 2 is formed as a bead part 3, and the bead part 3 is connected to the rim 5 having a rim valve 4.
It is well-known fact that when the conventional tubeless tire as shown in FIG. 31 goes flat while the vehicle is running, the car body is tilted due to the heavy weight of the vehicle because the air pressure of the tire gets low, and in addition, the control of the steering wheel and the brake operation becomes difficult.
The prior art, in order to solve the above-mentioned problem, uses a run flat tire that can make the automobile drive to some extent even though the tire goes flat. What is called the run flat tire is a tire that can make the vehicle drive to some extent even if the tire goes flat due to the air pressure rapidly dropping unexpectedly.
In the prior art, the following run flat tires are known.
Firstly, the side wall reinforced type run flat tire is known. The thickness of the side wall is reinforced to sustain the weight for a while by the structural strength of the side wall when the tire goes flat.
However, with the side wall reinforced type run flat tire, the side wall is thickening at the sacrifice of the vibration absorption ability to reinforce the structural strength of the side wall, which should be in charge of absorbing the vibration occurred by the road. Therefore, there are faults such as the decrease of the ride comfort, and the disadvantageous effect on the fuel mileage due to increase of the tire weight.
Secondly, the inner structural supporter type run flat tire is known. The inner structural supporter is installed around the rim wheel to sustain the weight for a while by the structural strength of the inner structural supporter when the tire goes flat.
The Japanese laid open patent application Tokkai Hei 07-276931 and the Japanese laid open patent application Tokkai 2002-096613 are known as the prior art of the conventional inner structural supporter type run flat tire. According to the conventional inner structural supporter type run flat tire, the car body will be supported by the inner structural supporter when the tire goes flat, therefore, the diameter of the inner structural supporter should be larger than that of the rim wheel.
The prior art 1 Japanese laid open patent application Tokkai Hei 07-276931
The prior art 2 Japanese laid open patent application Tokkai 2002-096613